feat: initial commit — BMAD tooling, Claude memories, firmware scaffold

Adds the complete project foundation:
- BMAD BMM workflow tooling (_bmad/)
- Claude slash commands, skills, and project memories (.claude/)
- ESP32 firmware scaffold (PlatformIO + Waveshare e-ink driver)
- .gitignore excluding _bmad-output/ and .pio/ build artifacts

Planning artifacts (PRD, architecture, epics) are intentionally not
tracked — they live in _bmad-output/ per project convention.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

_bmad/tea/workflows/testarch/bmad-testarch-automate/instructions.md

@@ -0,0 +1,50 @@
+<!-- Powered by BMAD-CORE™ -->
+
+# Test Automation Expansion
+
+**Workflow ID**: `_bmad/tea/testarch/bmad-testarch-automate`
+**Version**: 5.0 (Step-File Architecture)
+
+---
+
+## Overview
+
+Expands test automation coverage by generating prioritized tests at the appropriate level (E2E, API, Component, Unit) with supporting fixtures and helpers.
+
+Modes:
+
+- **BMad-Integrated**: Uses story/PRD/test-design artifacts when available
+- **Standalone**: Analyzes existing codebase without BMad artifacts
+
+---
+
+## WORKFLOW ARCHITECTURE
+
+This workflow uses **step-file architecture** for disciplined execution:
+
+- **Micro-file Design**: Each step is self-contained
+- **JIT Loading**: Only the current step file is in memory
+- **Sequential Enforcement**: Execute steps in order without skipping
+
+---
+
+## INITIALIZATION SEQUENCE
+
+### 1. Configuration Loading
+
+From `workflow.yaml`, resolve:
+
+- `config_source`, `test_artifacts`, `user_name`, `communication_language`, `document_output_language`, `date`
+- `test_dir`, `source_dir`, `coverage_target`, `standalone_mode`
+
+### 2. First Step
+
+Load, read completely, and execute:
+`./steps-c/step-01-preflight-and-context.md`
+
+### 3. Resume Support
+
+If the user selects **Resume** mode, load, read completely, and execute:
+`./steps-c/step-01b-resume.md`
+
+This checks the output document for progress tracking frontmatter and routes to the next incomplete step.